Properties of the Number 21328

Twenty-One Thousand Three Hundred Twenty-Eight

Basics

Value: 21327 → 21328 → 21329

Parity: even

Prime: No

Previous Prime: 21323

Next Prime: 21341

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 ⁴ × 31 × 43

Divisors: 1, 2, 4, 8, 16, 31, 43, 62, 86, 124

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001101010000

Octal: 51520

Duodecimal: 10414

Hexadecimal: 5350

Square: 454883584

Square Root: 146.04109010822947

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

a(n) = n*(n+1)*(4·n+5)/6. A16061

Expansion of 1/(1 - x - x² + x⁷ - x⁹). A225394

T(n,k) = Number of n X k 0..1 arrays with the number of 1's horizontally, antidiagonally or vertically adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero. A284199

Imaginary part of absolute Gaussian perfect numbers, in order of increasing magnitude. A102532

Triangle read by rows: T(n,k) = 2^k*A235998(n,k), n>=1, k>=1. A235999

Alternating sums of the squares of the numbers in sequence A080253. A217488

Expansion of g.f. A(x) = G( x*(1 + 2·x)*G(x) )^1/2 = G( x²*(1 + 3·x)*G(x) )^1/3, where G(x) is the g.f. of A370437. A370438

a(n) = (n!)³ * ∑_k=0..n k²/(k!)³. A368771

Numbers d·p where d is a perfect number and p<d a prime not dividing d. A165772

Admirable numbers n such that the subtracted divisor is > sqrt(n). A109321